1. Field of the Invention
The invention relates to methods and apparatuses for delivering materials having liquid and solid constituents such as salt and clay slurries. The invention has particular applicability for hauling sodium chlorate and its precursor salts.
2. Description of the Related Art
Many industrial processes employ large quantities of slurries, such as solutions. By way of example only, in a paper manufacturing process, large quantities of sodium chlorate are used as a bleaching agent. Sodium chlorate is typically manufactured from granular sodium at a sodium chlorate plant. Usually, granules are delivered to the chlorate plant in dump trucks, and are dumped into mixing pits near the plant. Water is then added to the pits, and the contents of the pits are mixed to form a slurry before being pumped off to the sodium chlorate plant. This process is not only time consuming, but also labor intensive.
Alternatively, the slurry may be pre-made and delivered in tanker trailers to the sodium chlorate plant. This approach is costly and inefficient since the heaviest component of the slurry is water. In effect, the shipper is required to pay freight for essentially hauling water. And due to the weight of water, a mobile tanker might easily exceed government imposed weight restrictions before the tanker is completely full, leading to further inefficiency.
After sodium chlorate is manufactured, it may be transported to a paper mill as a slurry. However, since sodium chlorate slurry may be appropriately 55% water by weight, doing so is costly and efficient for the reasons discussed earlier.
Due to the expense and inefficiency of transporting slurries, some shippers have resorted to hauling powdered sodium chlorate in rail cars and then adding water at the paper mill using a sparger system.
With a sparger system, a pump, external to the rail car, conveys water into the rail car while another pump conveys a mixture of liquid and solid from the rail car to an external mixing tank. Sparger systems do not typically employ any mechanical agitation in the tank. Rather, a sparger system continuously swaps the contents of the mixing tank and the rail car in an attempt to place all of the sodium chlorate into slurry form. There are a number of draw backs with sparger systems. First, they are time consuming to use. It typically takes about one half of a work day to turn a single rail car of dry sodium chlorate into slurry form. Second, sparger systems are typically not fully effective. Sometimes as much as 10 percent of a sodium chlorate load will not become slurry and will cake on the bottom of the mobile tank in which it is transported. In addition, the sparger system requires external equipment and excessive labor.
Accordingly, the present invention is directed to apparatuses and methods for minimizing the delivery cost of slurries, substantially obviating one or more of the limitations of the related art.
In a broader sense, the invention is directed to methods and apparatuses for making mixtures of solids and liquids or for suspending solids in liquids.
In accordance with the purposes of the invention, as embodied and broadly described herein, the invention includes a method wherein a mobile tank is incompletely loaded with an at least partially dehydrated component of a slurry. Sufficient room is left in the tank for a diluent to be later added and the slurry constituted in the mobile tank. The incompletely loaded tank is transported to a destination thereby obviating the expense associated with transporting the diluent portion of the slurry. At the destination, the diluent is added to the mobile tank and the slurry is constituted by activating a mechanical agitator within the mobile tank. After the slurry is constituted, it is off-loaded from the tank.
Although the method of the invention is not limited to any particular form of mechanical agitator, the invention may include an elongated conduit having a top end and a bottom end, the conduit having a propeller therein for drawing diluent from the top end and directing it towards the bottom end. When the propeller is activated, it initially draws liquid from the top of the load through the top end of the conduit and expels it at the bottom of the solids layer. This undermines the solids to provide quick blending, minimizing the opportunity for solids to remain unmixed.
In addition to the above, the invention may include one or more of the following aspects either alone or in combination with other elements:
various conduit configurations in a tank to facilitate the flow of a material from an upper region to a lower region,
a propeller encased with a conduit in a tank,
a fluid conveyer including rotating blades in a conduit,
a shaft extending through a conduit to drive at least one blade located in the conduit,
conveying fluid from an upper to a lower region of a tank at a rate of at least approximately 500 gallons per minute, and preferably at least 10,000 gallons per minute.
constituting a slurry in a mobile tank in which at least a portion of the slurry""s precursors are transported,
purposefully transporting a partially empty tank to a destination leaving room for diluent to be later added,
sequentially activating motors in each of a plurality of tank compartments,
undermining solids in a tank with a floor having one or more sloped regions,
locating the mixing propeller of a fluid conveyor close to the floor of a tank,
a compartmented tanker with an agitator in each compartment for separately mixing each compartment,
employing multiple fluid conveyors in a single tank,
employing a fluid conveyor in mobile road tankers, railcar tankers, stationary tanks, oceangoing vessels, other mobile vessels, or ISO containers,
using any of the above apparatuses or methods to transport and constitute sodium chlorate and its precursor salts,
using any of the above methods or structures in connection with slurries (including but not limited to clay and salt slurries), hazardous and nonhazardous waste, industrial mixtures, or any other mixture including those constituted from liquids an solid constituents, and
any other novel and nonobvious combination disclosed or suggested in the Background of the Invention, this brief Summary of the Invention, the Drawings and their Brief Description, the Description of the Preferred Embodiments, and the appended claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and are not intended to limit the scope of the invention, as claimed. The accompanying drawings are included to provide a further understanding of the exemplary embodiments and are incorporated in and constitute a part of this specification.